Paper-making machinery



Dec. 18, 1928.

E. A. OHLIN ET AL PAPER MAKING MACHINERY Filed March 29, 1928 the paperweb reaches the Patented Dec. 18, 1928.

UNITED STATES 1,695,972 PATENT OFFICE. j

ERIK ALEXANDER bHLIN AND FRANS 'OSKAR CARLSSON, OF HYLTEBRUK, SWEDEN.

PAPER-MAKING MACHINERY.

Application filed March 29, 1928, Serial N0. 265,715, and in SwedenApril 9, 1927;

The present invention relates to paper making machinery of the socalled-Yankeetype, e.- g., a machine provided with only one dryingCylinder and with a press section disposed between the drying cylinderand the couching press which press section is fitted with upper andunder drying felts.

In paper making machineries of the kind referred to used up to thepresent the press section situated. between the couching press and thedrying cylinder consists of a single pair of pressing rolls.Consequently, the paper web can only be given a comparatively smalldegree of dryness by pressing before reaching the drying cylinder,partlyowing to the fact that the pressure intensity between the pressingrolls must be kept within certain limits in order to prevent damagingthe paper web either by crushing or through impressions left on thesurface by the felts. I

In order to reduce the drying work ofthe drying cylinder and thusobtaining greater driving speed of the machinery, the greatest possiblepressure intensity between-the rolls is generally adapted, but thispressure is so high that the felts and especially the lower one is veryquickly worn out. The duration of the felts is usually so short that ifone wishes to entirely utilize same one can not perform the necessarychange of felts at occasions when the machinery for other reasons is outof work (if. i., on Sundays), but the machinery has often ,to be stoppedjust for the sake of refitting felts which obviously causes aneconomical loss.

The present invention has for its object an improvement pf paper makingmachineries of the kind referred to which partly gives the machinery agreater ca acity, because rying cylinder in a considerably driercondition, and partly causesan obvious saving of the felts owning to thefact that these are not subjected to such a high pressure as has beenthe case hitherto. v

To obtain this result thereare, according to the invention. provided atleast two consecutive pairs of pressing rolls situated'between thecouching press and the drying cylinder and all having a common upperfelt while each pair'of'pressing rolls has its separate under feltarranged in a known manner.

In the accompanying drawing there is shown by way of an example anembodiment of a paper making machinery fitted in accordance with theinvention. In the drawing 1 denotes the drying cylinderrotatorilymounted on the frame A of the machinery, 2 the paper web and 3 thecouching press of the machinery. According to the invention there arebetween the couching press 3 and the drying cylinder 1 provided twopairs of pressing rolls 4 and .5 respectively having the upper felt 7 incommon which is by means of two rolls 6 pressed against the dryincylinder 1, while each pair of pressing ro ls has its separate underfelts 8 and 9 respectively. It is suitable that the under felt 9 of thepress 5--which is situated near the couching press 3 and through whichthe paper web first passesis made of loose stuff produced byhard-twisted yarn so that the felt -oifers an easy transmission fortheWater. To the under felt 8 for the press 4 there is used a moretight-woven felt material with an entirely smooth surface, so thatimpressions on the comparatively moist paper web left by the press 5will entirely disappear when the paper web passes through the press 4. g

The presses 4 and .5 are in a known manner provided'with meansforregulating the pressure so'that, if an under felt at any occasion shouldbe heavil Worn the pressure on the same may be re need at the same timeas the pressure upon the other felt is increased. In this way it ispossible to adjust the duration of the-felts in such a manner thatthechan e of the felts can be. performed at suc times when the machineryfor other reason is out of use, 1. i., on Sundays.

I The invention is not limited to the embodiment described and shown,but may be varied in details without departing from [thespirit of it. F.i.,more than two presses may in certain, cases be provided between thecouching press and the drying cylinder. Further, the upper felt 7canalso be arranged in such a manner that it does not pass over theupper roll of the couching press.

What we claim is 1. An improved paper making machinery comprising asingle drying cylinder, a couching press, a plurality of pressesprovided between said couching press and said drying cylinder, the lastmentioned presses having a common upper felt and separate underfelts.

2. An improved paper making machinery comprising a single dryingcylinder, acouching press, a plurality of intermediate presses betweensaid couching press and said drying cylinder, a common upper drying feltand separate under felts for said intermediate presses, the felt for theintermediate press adjacent to the couching press being of com;paratively loose stuff produced by hardtwisted yarn, and the felt forthe int-ernicdi- 1 In witness whereof we have hereunto set our hand.

ERIK ALEXANDER ()HLIN. FRANS OSKAR CARLSSON.

